A Chiral Quadruple-Stranded Helicate Cage for Enantioselective Recognition and Separation

The self-assembly of enantiopure pyridyl-functionalized
metallosalan
units affords a homochiral helicate cage, [Zn8L4Cl8], in which the optical rotation of each
ligand is increased by a factor of 10 upon coordination. The octanuclear
cage featuring a chiral amphiphilic cavity exhibits enantioselective
luminescence enhancement by amino acids in solution. The cage exists
in two different crystalline polymorphic forms that possess porous
structures built of helicate cages interconnected by 1D channels or
pentahedral cages and have the ability to separate small racemic molecules
by adsorption but with different enantioselectivities.